Boost of solar water splitting on SrTiO3 by designing V-ions center for localizing defect charge to suppress deep trap

Abstract

The deep trap such as Ti3+ in SrTiO3 has a great influence on its photocatalytic performance in overall water splitting, acting as a recombination center of carriers. The applied defect engineering is focused on decreasing the Ti3+ concentration for enhancing solar water splitting mainly by doping low-valence metal ions, while the high-valence metal ions are noneffective. In this work, we doped trace V ions into SrTiO3 accompanied by the Al3+ from the Al crucible, promoting the photocatalytic activity in overall water splitting based on the photocatalysis evaluation. A series of advanced techniques are used to characterize the chemical and physical property changes in SrTiO3 aroused by V ions. Combined with the density functional theory, we found that trace V ions can cooperate with Al3+ to localize the defect charge around it, suppressing the formation of deep trap and increasing the amount of potential delocalized charge at shallow state, responsible for the boost of activity. This work provides another effective method to modulate SrTiO3-based photocatalysts in defect engineering.